Physical Therapy Assistant Practice Exam 2025 - Free PTA Practice Questions and Study Guide

The purpose of pulmonary function tests is primarily to document the extent of lung disease and predict prognosis. These tests measure how well the lungs are working by assessing airflow, lung volumes, and gas exchange. They are crucial for diagnosing conditions such as asthma, chronic obstructive pulmonary disease (COPD), and other respiratory disorders, allowing healthcare professionals to understand the severity of a condition and guide treatment decisions. By evaluating lung function, these tests help in predicting how well a patient might respond to treatment or how their condition may progress over time.

Other options focus on unrelated medical conditions; for instance, assessing heart function is done through cardiac testing, diagnosing kidney disease involves renal function tests, and osteoporosis is confirmed through bone density studies. Thus, option C distinctly captures the essential role of pulmonary function tests in monitoring lung health and prognosis.